Manipulation of the reproductive tract results in increased levels of prostaglandin, which may, in turn, reduce pregnancy rates in embryo recipients. Administration of a prostaglandin inhibitor prior to embryo transfer improves pregnancy rates in cows. Embryo transfer into heifers is more difficult and often requires additional manipulation of the uterus. This study was designed to determine whether administration of the prostaglandin inhibitor, flunixin meglumine, immediately prior to embryo transfer increases pregnancy rates in heifers. Heifers (n=466) were divided into two equal groups based on BCS (range=6-7) and weight (range=256-455). Estrus was synchronized in heifers by giving two injections of prostaglandin F_2" (PGF) eleven days apart with a two day stagger between groups. Heifers in each group were watched for estrus for four days following the second PGF injection. Each heifer detected in estrus (n~389; 83%) was palpated seven days later for the presence and location of an acceptable corpus luteum; development of the reproductive tract (uterine tract score; 1=prepubertal, 5=mature tract) and amount of uterine tone (uterine tone score; l=high tone, 2=medium tone, 3=low tone) were also estimated. The 352 heifers that had an acceptable CL were paired based on day of detected estrus, body condition score, body weight, and uterine tone score. One heifer of each pair was randomly assigned to receive 10ml of flunixin meglumine (IM) just prior to embryo transfer. Time between injection until completion of embryo transfer ranged from 2-25 minutes. All heifers received a single frozen/thawed embryo transferred by one of two experienced technicians. Data collected at the time of transfer included cervix score (1-3; 1=easily penetrated, 3=difficult), ease of transfer score (1-3; l=gun easily manipulated to site of transfer, 3=difficult), embryo placement in the uterine horn (U=upper 1/3, M=middle 1/3, L=lower 1/3), and technician. Pregnancy results were obtained 90 days after transfer via rectal palpation. The logistics procedures and chi-square analysis of SAS were used for data analysis.
College and Department
Life Sciences; Plant and Wildlife Sciences
BYU ScholarsArchive Citation
McNaughtan, Jared William, "The Effect of Prostaglandin Inhibitor on Pregnancy Rates of Heifer Embryo Transfer Recipients" (2004). Theses and Dissertations. 237.
embryo transfer, prostaglandins, flunixin meglumine, cattle